Phones, laptops, electric cars – batteries are everywhere. And to meet the expectations of today’s consumers, these batteries are increasingly light, more powerful and designed to last longer. Currently the most important technology for these applications is the lithium-ion battery technology: but the technology is expensive and contains a flammable liquid, which may represent a safety hazard, when the battery is abused. To satisfy the growing demand from emerging markets (electric cars, for example, and renewable energy storage), researchers from Empa, the Swiss Federal Laboratories for Materials Science and Technology, and the University of Geneva (UNIGE), Switzerland, have devised a new battery prototype: known as “all-solid-state”, this battery has the potential to store more energy while maintaining high safety and reliability levels. Furthermore, the battery is based on sodium, a cheap alternative to lithium.